the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 24 Feb 2026
Respecting the boundaries: balancing climate adaptation and Earth system resilience
Abstract. Anthropogenic climate change necessitates not only rapid climate mitigation but also widespread adaptation. It is common knowledge that climate adaptation cannot replace and must not derail mitigation efforts. Yet surprisingly little is known about the existing pressures of climate adaptation on the Earth system. The Planetary Boundaries framework sets biogeophysical limits for critical Earth system processes. In an explorative analysis, existing interactions of climate adaptation with proxies for the Planetary Boundaries are investigated. Linking research from various domains into an attribution analysis, it is found climate adaptation currently contributes ~25.56 percent of annual greenhouse gas emissions and ~74.08 percent of annual human freshwater withdrawals. Climate adaptation even affects the stratosphere: the ozone hole is to a considerable degree an unintended consequence of climate adaptation. Climate change already drives some of these impacts. However, fuelled by factors such as economic and population growth, the majority of these effects would likely also have occurred under Holocene climates. This proves both the importance and the urgency of respecting safe boundaries when accelerating global climate adaptation.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Earth System Dynamics.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.- Preprint
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Status: final response (author comments only)
- RC1: 'Need to be consistent about term 'climate adaptation'', Anonymous Referee #1, 01 Jun 2026
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RC2: 'Comment on egusphere-2026-79', Anonymous Referee #2, 28 Jun 2026
Thank you for inviting me to review the paper “Respecting the boundaries – balancing climate adaptation and Earth system resilience” by Ott et al.
Sometimes, when you come across an idea, it seems such an obvious point, yet to my mind there is relatively little existing research on what this paper addresses. Basically, what additional future emissions will arise from adapting to climate change? We have all heard the ironic points made, for instance, that as the planet warms, people will buy AC units, which use fossil fuels to run. And so amplify the problem.
Here, the authors quantify this positive feedback, estimating its magnitude at around 25%. An interesting parallel calculation shows that this rises to around 70% for freshwater use (e.g. increased crop irrigation in a warming world).
I like the paper, but the version reviewed here feels slightly rushed. Here are a few suggestions if the authors would like to prepare a new version, which may help towards a high-standard paper suitable for ESD.
- On the definition of adaptation feedbacks, make this very clear – it is the additional energy consumption likely to be associated with adapting to a new climate. It is not that we plan for a specific emissions scenario (i.e. a high-mitigation one) but then find we cannot adapt fast enough – so we burn extra emissions.
- The reason for (1) above is that the title is slightly misleading. I was expecting to see a “U”-shaped graph, perhaps of cost to society (y-axis) against emissions reductions (x-axis). On the left-hand side of the plot, emissions would be reduced so quickly that it would be prohibitively expensive. On the right-hand side, we choose not to reduce emissions so quickly, but there are major impact costs from a changing climate, despite attempts to adapt to climatic change.
- Do the 25% and 70% figures depend on the emission scenario – i.e. the SSPs? And on the future time?
- Do the standard SSPs partition emissions so that the “extra bit” causing adaptation is identified by scenario and future time (e.g. the standard Meinhausen papers)? Although the authors make good use of the literature, I did at times struggle to understand how the analysis fits within the context of existing work.
- The authors have published extensively on climate boundaries (“guardrails”) over the years, and the paper, including the title, suggests that readers can expect much on this here. But there is no diagram or plot where this jumps out. Is there a way to create a figure that relates back to the influential figures in the authors’ earlier papers?
- Please include a couple of specific examples in the Abstract. This always helps the general reader. For emissions, state the example of increased energy use with AC units, and for freshwater, state the example of increased water use for irrigation.
- Then, with the two examples in the Abstract, the reader can refer to the key Table 1 for other examples. I really like Table 1, and this should be the main focus of the paper, in my opinion.
- Some of the diagrams appear slightly rushed, not at publication quality, and are also slightly amateurish. Figure 3 might have been better as a histogram, with the left part as a two-bar histogram and the right part as a single bar with subdivision (as shown already).
- Figure 4 has far too many vertical tick marks, an excessively small legend, and unnecessary vertical and horizontal lines.
- Some of the previous work on planetary boundaries is cited and referenced, especially in the Conclusions. I found some of the terms used (e.g. “niches”) to be quite specific to the boundaries approach. A clearer explanation of the terms used would be helpful. Indeed, as the paper is quite text-based, it might help to include a table of key terms or words used, and their explanations.
This is an important paper, but it feels rushed. I am very happy to review any revised manuscript. With care and attention, I believe it could make a valuable contribution to ESD.
Citation: https://doi.org/10.5194/egusphere-2026-79-RC2
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- 1
This article looks at the Earth system impacts of measures referred to as ‘climate adaptation’. These measures include modifying the flow of water, building and maintaining residential structures, and refrigeration. They discuss general findings of the literature and provide approximate estimates for the CO2e emissions associated with the measures.
I feel this is a useful article that makes some valuable points. However I think it needs major revision prior to publication. This revision should clarify the language, to prevent dangerous misinterpretation, and should also restructure the text to reduce repetition and focus the message.
Most importantly, the authors need to take greater care in distinguishing between 1. the adaptation to local climate for any reason, and 2. adapting to climate change. The latter is what is typically meant by ‘climate adaptation’, yet the authors are inconsistent in their use of the term, sometimes applying it to one and sometimes the other. For the purposes of this article I might suggest they differentiate ‘local climate adaptation’ vs. ‘climate-change adaptation’, where the second is a component of the first.
Once the authors have decided how to deal with this, the abstract needs to be significantly rewritten, to first introduce the reader to the idea of what is meant by adapting to the local climate, so that the meaning of the ’26%’ of emissions and ’74%’ of freshwater are clear. Otherwise the reader will assume that these amounts are for adaptation to climate change, which would be incorrect. Many parts of the manuscript will need to be adjusted to be consistent with this (too numerous to list here).
The manuscript could also be greatly improved by reducing repetition (especially in section 1) and focusing on the novel findings.
Specific comments:
- I didn’t find the four functional mechanisms (line 120) very intuitive. It was hard for me to understand why the first two would be called ‘flow’ and “boundary’, given what is meant by them. Also, I wondered why is a green wall would be functionally different than a cement wall? However perhaps these are better explained in the cited paper (Ott et al., 2025 submitted)?
- calling all refrigeration 'climate adaptation' seems like a stretch, since much of it is to preserve food... is it true that's what being done here?
- Line 171 phrase starting ‘However, one should also account…’ was very hard to understand.
- The disagreement with Abajian et al., 2025 seems important - I’d request more detail regarding this comparison. Is it true that they only included CO2? What specifically is wrong with their analysis?